More particularly, the microorganisms studied are two filamentous fungi, Byssochlamys nivea and Neosartorya fischeri and a yeast, Zygosaccharomyces bailii.
These contaminants of food products can develop on the fruit-based products, giving them, particularly for Byssochlamys nivea, unpleasant notes of the plastic or antiseptic type; the growth of Neosartorya fischeri is responsible for spoilage and the appearance of mycotoxins, whereas as that of Zygosaccharomyces bailii causes a formation of gas.
These microorganisms particularly in the form of spores, exhibit a very high heat resistance which allows them to persist, even after conventional pasteurization treatments, which are applied in the food industry.
The existing tests allowing the detection of these microorganisms consist in altering the samples of a selective medium by taking advantage of, as a selection factor, the heat resistance of the filamentous fungi or the resistance of the yeast to certain preservatives conventionally used in the sector, such as benzoic acid. However, this type of detection involves cultures and, what is more, fairly long cultures, namely from several days to several weeks, which makes them practically unusable in the food sector since they could involve preserving the products, which may be contaminated, for a very long time.
The search is therefore underway for a detection test allowing the very rapid detection of these microorganisms, it being possible for the said test to be carried out in a few hours at the most, in order to find out rapidly if the sampled product can continue or otherwise to be treated in the subsequent stages.